Shaykh Ahmed An-Najamee said in Al- (Fataawaa Al-Jaliyyah, volume 2: )
“It is not permissible for the beginning student of knowledge to declare someone an innovator, or declare someone a disbeliever until he is Qualified to do that.
And he must refer the matter back to the senior (Kibaar) people of knowledge in particular, because Allaah, the Most High, says: “If only they had referred it to the Messenger or to those charged with authority among them, the proper investigators would have understood it from them (directly).” (An-Nisaa:83)
*It is not appropriate for the beginning student of knowledge to declare people unreliable (Jarh), or declare people innovators(Tabdee’) from his ownself.
However, he must take from the statement of the people of knowledge who are considered (authorities). And there is no harm in him speaking from one of the scholars if he is sure of their statement in declaring someone unreliable (At-Tajreeh). And Allaah is the Giver of success…
the matter of describing someone with innovation and boycotting the innovator, this is (for) whoever the scholars declare to be an innovator. And do not be hasty O you small students, to pass judgment on any person with the declaration of innovation, even if the person has with him an innovation, until you present that back to the scholars and they assist you in that. Without this (referring back to the scholars), then you all do not do anything of that.”
Also Shaykh Ahmed An-Najamee has said else where “…that the common people and the beginning students of knowledge, it is not appropriate for them to be hasty in passing judgments on others besides them until they refer back to the people of knowledge, who are greater than themselves, and those who know these affairs. Indeed they have dealt with these affairs for a long time…”
{Fataawaa Al-Jaliyyah, volume 2 }